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EMMC / SD learning notes

2022-04-23 13:07:00 【MyeDy】

Command index	type	Parameters	The reply	abbreviation	Command specification
CMD0	bc	00000000	-	GO_IDLE_STATE	Reset the device to idle state
CMD0	bc	f0f0f0f0	-	GO_PRE_IDLE_STATE	Reset the device to pre-idle state
CMD0	-	fffffffa	-	GO_INITIATION	Start the replacement boot operation

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Command index	type	Parameters	The reply	abbreviation	Command specification
CMD1	bc	[31:0] OCR	R3	SEND_OP_COND	request idle Status sent by the device at CMD Send its line OCR structure

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Command index	type	Parameters	The reply	abbreviation	Command specification
CMD2	bc	[31:0] Fill bit	R2	ALL_SEND_CID	Request device at CMD Send its line CID Number

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Command index	type	Parameters	The reply	abbreviation	Command specification
CMD3	ac	[31:16] RCA [15:0] Fill bit	R1	SET_RELATIVE_ADDR	Assign a relative address to the device

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Command index	type	Parameters	The reply	abbreviation	Command specification
CMD9	ac	[31:16] RCA [15:0] Fill bit	R2	SEND_CSD	SEND_CSD The addressed device is CMD Send its equipment specific data online （CSD）

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Command index	type	Parameters	The reply	abbreviation	Command specification
CMD7	ac	[31:16] RCA [15:0] Fill bit	R2	SELECT/DESELECT_C ARD	stay stand-by and transfer Between states or program- ming and disconnect Command to switch devices between States . In both cases , The device is selected with its own relative address and deselected with other addresses ; Address 0 Deselect all devices .

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Command index	type	Parameters	The reply	abbreviation	Command specification
CMD13	ac	[31:16] RCA [15:0] Fill bit	R1	SEND_STATUS	The addressed device sends its status register

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Command index	type	Parameters	The reply	abbreviation	Command specification
CMD18	adtc	[31:0] Data address 1	R1	READ_MULTIPLE_ BLOCK	Continuous transmission of data blocks from the device to the host , Until interrupted by the stop command , The number of blocks or required for transmission .

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wait for 74 A clock
CMD0 Reset SD Card to idle state
CMD8 send out SD Card interface conditions , Contains the voltage information supported by the host , And ask if the card supports . The reserved bit should be set to 0.

Command index	type	Parameters	The reply	abbreviation	Command specification
CMD8	bcr	[31:12] Keep a ,[11：8]VHS,[7:0] Check mode	R7	SEND_IF_COND	send out SD Card interface conditions , Contains the voltage information supported by the host , And ask if the card supports . The reserved bit should be set to 0.

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ACMD41 Send card support information (HCS). send out ACMD Need to send first CMD55.

Command index	type	Parameters	The reply	abbreviation	Command specification
CMD55	ac	[31:16]RCA [15:0] Fill bit	R1	APP_CMD	Tell card , The next command is an application specific command , Instead of standard commands .

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Command index	type	Parameters	The reply	abbreviation	Command specification
ACMD41	bcr	[31] Keep a [30]HCS(OCR30) [29:24] Keep a [23:0]VddVdd voltage (OCR[23:0])	R3	SD_SEND_OP_COND	Send card support information (HCS), And ask the cartoon to return through the command line OCR Register contents . When the card is received SEND_IF_COND when ,HCS It works . The reserved bit is set to 0.CCS Bit correspondence OCR[30]

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Next SD Card initialization is CMD2 and CMD3, Roughly the same as MMC The card process is the same . There are some commands behind SD and MMC It's different , such as switch Your orders are different ,SD The card uses ACMD6 To define the width of the data, and so on , and MMC It's using CMD8 Come on switch.

Command index	type	Parameters	The reply	abbreviation	Command specification
ACMD6	ac	[31:2] Fill bit [1:0] Bus width	R1	SET_BUS_WIDTH	Define the width of the data bus (‘00’=1bit,‘10’=4bit). The accepted data bus is defined in SCR In the register .